New Mars Orbiter Will Be a Super-Sniffer

The first joint U.S.-European mission to Mars now has a plan for its toolkit.
Scheduled for launch in 2016, the ExoMars Trace Gas Orbiter will study the chemical composition of Mars’ atmosphere with a suite of instruments specially suited to the task. These instruments are expected to take measurements 1,000 times more sensitive than those by previous Mars orbiters.
“To fully explore Mars, we want to marshal all the talents we can on Earth,” said European Space Agency scientist David Southwood. Traveling around Mars in a circular path, the ExoMars spacecraft will record spectra of the sun as its telescope picks up the light that reaches it through orbital sunrise and sunset. Depending on the composition of gas in the atmosphere, sunlight will pass through it differently.
“If you take the spectra fast,” said NASA Jet Propulsion Laboratory researcher Geoffrey Toon, “you can measure the gas abundance at many different heights above the planet — 70 measurements as the sun rises, and 70 as it sets.”